I installed the WinUSB driver through Zandig, as directed on the wiki.

I sat there scratching my head as to why it wasn't working or where the options were, and uninstalled and reinstalled the drivers a few times.

I realized that I was on 5.0, not a dev build with Bluetooth Passthrough support.

I installed the latest devbuild, dolphin-master-5.0-1905-x64

Couldn't figure out why it wouldn't recognize the adapter, uninstalled and reinstalled the drivers a few times, rebooting each time.

Realized that I had to manually configure the VID and PID in dolphin.ini, and I used a hex to decimal converter to get the right values.

I booted up a Wii game, Metroid Prime Trilogy.

From here, it gets funky. It doesn't work, no matter how many times I tell it to sync in Dolphin and press the official Nintendo (non motion plus) Wiimote's red button simultaneously. Except one time it did. It appeared to work. Didn't have a sensor bar as of yet, so I grabbed some candles. In the time it took me to do this, my Wiimote lost connection and refused to connect again.

So I tried various other steps like rebooting Dolphin and rebooting the computer and running Dolphin as admin, and after many attempts I got it to connect again, after trying the sync process in one go many times. Sensor worked fine. Vibration worked fine. Buttons worked fine. But a minute later it dropped again and refused to reconnect.

EDIT 1: I nearly forgot - I swapped the USB position around a few times in the process of troubleshooting. It was on a USB 3.0 port on the back of my machinek, but I figured the signal was getting lost maybe so I swapped it to a USB 2.0 on my monitor, that runs through an extension cable. No dice either way.

Bluetooth passthrough seems pretty patchy depending on which adapter you use. I've got no experience with your adapter, but I tried a few others and they all had issues with range or needing to re-sync each time, only one wiimote working at a time, etc. In the end I bought a broken wii for £5, lifted the adapter out of it, and wired it into my orb sensor bar. All usb powered, and the bar has a handy switch to turn it on or off whenever it's not in use. :-)

Did more experimentation. Found my Wii's power brick and confirmed the Wiimote worked there.

I downloaded an old version of the drivers needed and while I'm not certain that helped, things appear to be a bit more stable. Connecting is still a total pain, taking several attempts and restarts to finally connect, but once it's connected it usually stays connected until Windows is restarted. In Metroid Prime Trilogy, it seems to work flawlessly. In Smash Brothers Brawl, it seems to send strange ghost inputs. I can hold down a button or direction on the joystick and it will continue to send inputs sporadically; this means I would be holding the joystick and I might stop and start moving again, or I might tap the A button and it will send the input twice. Bluetooth bandwidth issue, perhaps? Smash uses Wiimote audio, where Prime Trilogy does not.

In any case I got it working "Good Enough." Again I am not sure if that old driver package helped or not but I will upload it later and post it here for anyone reading this in the future.

That means it's dropping packets, which usually means the adapter doesn't work well enough for BT passthrough. Unfortunately, they don't all work great with this feature and yours doesn't appear to work great (there have been other reports of issues with your adapter on the forum)

Although this is unlikely to have any effect, try uninstalling the Bluetooth drivers. You don't need them, since Dolphin is using the adapter *directly* and giving it to the game (and it's the game and its own Bluetooth stack which are responsible for managing the adapter).

I should have suspected as much. I knew the issue was with the Bluetooth adapter not sending or receiving information correctly, I don't know why I assumed bandwidth when packets make more sense. This explains why it's sending inputs twice; it's dropping the continued input event packet, which the emulator will interpret as a depress, and the next packet will send the proper continued input event information, which the emulator will interpret as repressing. Doesn't explain why one game might have this issue and the other might not, I'll have to experiment on more games.

I should see about updating the Wiki page to say this adapter might not be recommended.

I agree with modifying the wiki to not recommend this adapter. SGTNAPALM is the third user, including me, that has had problems with this adapter. My woes are throughly documented here but the main complaints are that this adapter does not remember pairing for more than one wiimote and last night I discovered that it starts becoming unstable after a while and has to be turned off an on again. Poor Mario kept falling off platforms .

I signed up to the wiki but cannot edit the page. I used to be able to but it appears that maintenance has been limited to a trusted core of contributors, understandably.